Criteria for using the Superpave gyratory compactor to design airport HMA mixtures

Asphalt concrete pavements for commercial airport applications in the USA are constructed according to guidelines in Item P-401, ‘Plant Mix Bituminous Pavements’, Federal Aviation Administration (FAA) Advisory Circular 150/5370-10E. Item P-401 specifies the material characteristics and construction requirements for airport asphalt pavements, but does not currently provide guidance for using the Superpave gyratory compactor (SGC) in the preparation of specimens used in the design of hot mix asphalt (HMA) mixtures. Nearly all state departments of transportation in the USA use the SGC along with the Superpave mix design procedure. Since most HMA mixes are used in roadways, many asphalt contractors no longer maintain expertise and equipment for conducting the Marshall mix design procedure currently used by the FAA. The lack of contractors familiar with the Marshall method may become a significant problem for the FAA in the future. This paper describes a laboratory study of the HMA mix design for airport pavements, which uses the SGC. The purpose of the study was to determine the number of gyrations with the SGC needed to design asphalt pavement mixtures for airports. A value of 70 gyrations is recommended for further evaluations based on the comparisons of volumetric measurements of HMA mixture specimens compacted using Marshall compaction with specimens from the same mixture compacted using Superpave gyratory compaction.